<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>    
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>登录状态判断</title>
</head>
<body>
	<c:set var="uid" value="${6}" scope="request" ></c:set>
	<c:set var="logged" value="${not empty uid}" ></c:set>
	<c:if test="${not logged}">
		<form id="" method="post" action="">
			用户名：<input type="text" name="username"/>
			密码:<input type="password" name="password"/>
			<br/>
			<input type="submit" value="提交">
		</form>
	</c:if>
	<c:if test="${logged}">
		登录成功！
	</c:if>
</body>
</html>